Projection illumination systems are used for the microlithographic production of microelectronic devices, in particular semiconductor devices or devices for micro- and nanotechnology. In order to produce structures with very small dimensions, it is desirable to image the structures in the projection illumination system with a high degree of accuracy. Even the smallest changes in the optical elements used in the projection illumination system with respect to their form, composition or their position in the optical arrangement can result in corresponding aberrations and thus to defectiveness of the devices to be produced.
Accordingly it is known to use methods for positioning and/or adjusting optical elements in optical arrangements of a projection illumination system, which methods conform to the highest desired properties in terms of the accuracy of the positioning. DE 102 25 266 A1, for example, describes an imaging apparatus of a projection illumination system for microlithography, in which manipulators with piezoactuators are used in order to manipulate and position relevant optical elements, such as for example optical lenses, mirrors or the like.
The disclosure of DE 102 25 266 A1 and of U.S. Pat. No. 6,150,750, which describes piezoactuators in the form of linear piezo drives, are incorporated by reference herein in their entirety.
Although a very exact positioning of optical elements is already possible with the linear piezo drives, as they are described in the previously mentioned documents, there is furthermore a desire for efficient operating methods which enable, in addition to simple and effective operation of the manipulators, at the same time extremely exact positioning with a high degree of accuracy.
It has been shown that the fact that the movement of the linear piezo drives and/or the movement of the optical elements which are moved thereby or of the gear elements such as actuating levers or the like which are possibly provided between the optical element to be manipulated and the linear piezo drive is delimited by abutment elements results in interactions with the abutment element possibly resulting in influences on the optical element. When the abutment element comes into contact in the peripheral movement region of the manipulation apparatus, the optical element can be negatively affected with corresponding negative effects on the imaging properties. It is desirable for this reason to use a corresponding positioning method which takes into account these possible negative influences.